A pivotal sash window adapted for installation in a master frame of a sash window assembly is well-known. The sash window assembly typically has opposed, vertically extending guide rails to enable vertical reciprocal sliding movement of the sash window in the master frame while cooperatively engaged with the guide rails. The sash window has a top sash rail, a base and a pair of stiles cooperatively connected together at adjacent extremities thereof to form a sash frame, usually a rectangular frame. Typically, a pair of spaced tilt-latches are installed on, or in, opposite ends of the top sash rail.
Each tilt-latch is generally comprised of a housing having an outward end opening and a latch bolt disposed within the housing. A spring disposed within the housing generally biases the latch bolt through the outward end opening to engage the guide rails of the master frame. The latch bolt has a control button to allow for actuation of the latch bolt. An operator's finger engages the button to actuate the latch bolt wherein the latch bolt is retracted into the housing. This releases the latch bolt from the guide rail. When the latch bolts of the opposed tilt-latches are actuated simultaneously, the sash window can then be pivoted from the master frame.
A tilt-latch mounted in a top sash rail is typically called a flush-mount tilt-latch. An example of this type of tilt-latch is shown in U.S. Pat. No. 5,139,291, assigned to Ashland Products, Inc., the assignee of the present invention. To accommodate the flush-mount tilt-latch in the top rail, a header slot is punched or routed in the top rail. The slot forms a pair of opposing, longitudinal header rails. The tilt-latch disclosed in U.S. Pat. No. 5,139,291 has a longitudinal groove on opposing sidewalls of the latch. This tilt-latch is installed in the header slot of the top rail by inserting the latch from the side of the sash frame wherein the longitudinal grooves receive a respective one of the header rails wherein the tilt-latch is retained in the top sash rail.
Other flush-mount tilt-latches have been designed to be preferably installed by inserting the tilt-latch perpendicularly into the header slot from the top of the top sash rail. These tilt-latches are typically "snapped into" the header slot although the tilt-latches can usually also be slid into the header slot from the side of the sash frame. To retain these "snap-in" type latches in the top rail, the latches typically have a plurality of flared tabs, or ramps, on sidewalls and/or a rear wall of the tilt-latch. The tabs can be rigid or resilient. In either case, the tilt-latch is snapped into the header slot wherein the tabs abut a bottom surface of the top sash rail. A cover of the housing abuts a top surface of the top rail. Thus, the header rail is grasped cooperatively by the housing cover and the tabs.
FIG. 1 discloses a side-elevational view of a prior art snap-in type tilt-latch 1. FIG. 2 discloses a partial cross-sectional view of the tilt-latch 1 of FIG. 1 installed in a header slot 2 of a top sash rail 3. The tilt-latch 1 has a housing 4 and a latch bolt 5 within the housing. The housing 4 has a plurality of resilient tabs 6 on sidewalls 7 of the housing 4 (one tab 6 shown on each sidewall 7 in FIG. 2). The tabs 6 have an inverted U-shaped slot 6a cut around the tabs 6 that allows the tabs 6 to flex inward towards the latch bolt 5. When the tilt-latch 1 is installed into the header slot 2, an inclined surface 8 of the tab 6 frictionally engages the header rail 2a wherein the tab 6 flexes inwardly until it passes completely by the header rail 2a where, ideally, it snaps back to the position shown in FIG. 2. In this installed state, the header rails 2a are grasped cooperatively by a housing cover 9 on a top surface of the header rail 2a and by the tabs 6 on a bottom surface of the header rail 2a. In certain instances, due to irregularities in the dimensions of the tilt-latch 1 and/or the top rail 3, the tabs 6 do not snap back to their normal position upon installation. Thus, as shown by the phantom lines in FIG. 2, the tabs 6 remain in an inwardly flexed condition wherein the tabs 6 may engage the latch bolt 5. This engagement restricts, obstructs and/or prevents movement of the latch bolt 5. Thus, the latch bolt 5 can be left in a partially retracted or retracted state that could allow the tilt-latch 1 to disengage from the guide rail allowing the sash window to pivot uncontrollably from the window assembly. Accordingly, the engagement problem can render the tilt-latch 1 inoperable.
Another type of snap-in tilt-latch can have rigid tabs extending from sidewalls of the housing. Such a prior art latch is shown in FIGS. 3 and 4. These tabs 13 do not have a slot cut around a portion of their peripheries but extend integrally from the sidewall of the latch. As shown in FIG. 4, the sidewall 17 is of a thickness that does not allow easy flexing upon installation. Furthermore, the latch bolt 19 fills the entire housing 21 preventing the sidewalls 17 from flexing inward a suitable distance for installation. For installation, the header rail must flex as the tilt-latch is snapped into the header slot. If the rigid tabs 13 do not snap back to their original position upon installation, the sidewall can be forced inward thus engaging the latch bolt. Again, this would restrict or prevent movement of the latch bolt making the tilt-latch inoperable.
The present invention is provided to solve these and other problems.